Method and apparatus for charging thermostatic devices



Aug. 9, 193

P; E. CATE METHOD AND APPARATUS FOR CHARGING THERMOSTATIC DEVICES 2Sheets-Sheet 1 Filed Aug. 27; 1935 P. E. CATE Aug. 9, 193a METHOD ANDAPPARATUS FOR CHARGING THERMOS'I'ATIC DEVICES Filed Aug. 27, 1935 2Sheets-Sheet 2 Patented :Aug. 1938 um'r azo STATES PATENT OFFICE METHODAND srrsasros son cnsnonsc 'rnsmuos'rs'nc DEVICES Paul E. Cate,Knoxville, Tenn., assignor to The Fulton Sylphon Company; Knoxville.Tenn, a corporation oi Delaware Application August 21, 1935, s ri l No.5am

bulb intended to be subjected to the temperature Y 1 bywhich thedeviceis controlled, a combined bellows head and stop to which the bulbis con nected by a capillary tube, and a bellows member connected at oneendto the head and having an opposite 'end wall adapted to be movablerelatively to the combined head and stop in response to the temperaturevariations to which the thermostatic bulb is exposed. The movementsexpansion and contraction of asuitable thermo responsive liquid withwhich the assembly of bulb, tube. and bellows is charged.

with the methods and apparatusheretoiore available many diiflcultieshave been encoun- 25 tered incharging thermostats of this type on a.production basis. For example, although-it is vitally important to. theefllcient operation of such devices that the assemblies be free from 1 vair, moisture and other foreign substances after charging, much troublehas been experienced in carrying out the charging operation under such.conditions as to insure this result. 'It is of per-' haps even greaterimportance in the case of a liquid filled thermostat that thisparticular form 35 of assembly be completely filled with the chargingliquid; however. the attainment of this condition has also been adiflicult task, particularly because of the fact that the capillaryconnecting tube hasonly a. very small bore, the diameterthereof being onthe order of .025". It has also; been necessary to exercisegreat care inhandling the charging liquid in order to avoid the inclusion of anyforeign matter which might stop up this small tubing.

It is therefore one of the objects of the present invention to provide anovel methodand apparatus for charging thermostatic assemblies whichwill overcome the dl'fllculties hitherto ex- 50 perienced in this workand will be capable of accurately and eillciently charging such devicesona production basis.

proved procedure and mechanism for efllciently so evacuating a number ofthermostatic assemblies of the bellows end wall are controlled by theand then charging them with accurately determined quantities of asuitable liquid.

A further object is to provide a method and apparatus whereby theevacuation and charging of thermostatic devices of the type referred to5 may be carried out with a minimum of manual operations and a' maximumof protection against I undesired conditions in the finished product.

Still another object is to provide a novel procedure and arrangement ofmechanism whereby thermostats oi this character may be quickly andeillciently charged under accurately controlled conditions and withoutloss or wastage oi" the charging. liquid.

A still further object is to provide an apparatus for the purposedescribed wherein all of the operations performed during the chargingcycle may be controlled by the mere opening and closing of variousvalves in an established sequence.

- These and other objects. includin'g the provision of variousmechanical elements'of novel construction for performing certain of thein.- divldual functions required by the method'andgeneralapparatusarrangement of the invention, will appear more fully from aconsidera- 1 tion of the detailed description of the embodi ment of theinvention which follows. Although only one mechanical exempliflcation ofthe method and apparatus of the invention has been described andillustrated in the accompanying, drawingsfiit is to be expresslyunderstood that these drawings arefor the purpose or illustra tion onlyand are not tobe construed as defining the scope of the invention,reference being had for this purpose to the appended claims. Referringnow to the drawings. wherein. like reference characters indicate likeparts throughu out the several views:

Fig. 1 is a diagrammatic showing of one ar- 4 rangement of thermostatevacuating and chargin equipment embodying both the method and apparatusfeatures of the present invention;

Fig. 2 is a side view. with certain parts shown in section, of one formof thermostatic assembly assemblies are connected to the evacuating andAnother object is to provide a new'and imcharging equipment: j

Fig. 4 is a sectional view of one of the packless valves of Fig. 1 whichcontrol the application of pots of Fig. l by which the charging liquidis forced into the thermostatic assemblies under pressure so as toinsure complete filling thereof.

Referring first to Fig. 2, the thermostatic assembly therein shown, forthe charging of which the apparatus of Figs. 1 and 3-7 is especiallywell adapted, consists of a thermostatic bulb 8 having at one end a tip9 of reduced diameter, a combined bellows head and stop i having athreaded boss ll extending from one end, abellows I2 I secured to headIn in any suitable manner as at l3 and having a movable end wall l4, anda capillary tube i5 connectingthe interior of bulb 8 with combined headand stop in and communicating with the space between said head and stopand the bellows l2. Before charging, the

tip 9 of bulb 8 is cylindrical, as indicated in broken lines in Fig. 2,and is open at its outer end, being crimped and closed to the form shownin solid lines in Fig. '2 at the end of the charging operation by anysuitable form of mechanism.

In order to accurately and efficiently charge thermostatic assembliesof. this character, a

novel arrangement of mechanism, diagrammatically illustrated in Fig. 1-,has been provided for first evacuating the assemblies so.as to insurethe removal of all air, moisture and other foreign matter therefrom, andthen filling them with a suitable thermoresponsive liquid which isforced into the assemblies under pressure to insure proper fillingthereof, each assembly being so 1 supported during this operation thatthe volume thereof, and consequently the volume of liquid which can beplaced therein, is definitely and uniformly limited. The system is alsoso arranged that, after the charging operation is completed, thethermostatic assemblies may be disconnected from the charging manifoldswithout the loss of any of the charging liquid, means being provided forwithdrawing to a suitable reservoir that liquid which remains .in themanifolds after the assemblies have been completely filled and forperiodically returning the liquid thus withdrawn to the main source ofsupply.

In the equipment diagrammatically illustrated in Fig. l, thetips 9 ofany desired number of thermostaticassemblies may be connected to one ormore charging manifolds l6 by means of sealing connectors indicatedgenerally at H, while the bellows ends'of the assemblies are supportedin suitable clamps I! which hold the bellows at the proper degree ofextension during the charging operation so as to insure the charging ofa definite and uniform amount of liquid in each of the assemblies.

As shown in Fig. 3, each of the sealing 'con- .nctors l1 comprises anexternally threaded body portion lfl mounted on manifold l8 and communi-I eating with the interior of the latter'through a passageway ofsubstantially the same diameter as the tip 8 .ofthe thermostaticassembly.

Threaded onto body portion I9 is a hollow clamping nut 2| within whichis supported a cupshaped guide member 22 the upper end of which is intelescoping engagement with a downwardly depending boss 22 of reduceddiameter formed integrally withbody portion l9. Housed within guidemember 22 is a sealing gland 24 madeof any suitable relatively softsubstance, such as rubber, and having a passage 25 therethrough coaxialwith passage 20 and of such size as to receive with a frictional fit thetip 8 of one of the thermostatic assemblies. Clamping nut 2| and guidemember 22 are also provded with suitable openings to permit theinsertion of tip 8. With this construction, the bore of tip 9 may bebrought into direct communication with passage 20 and through saidpassage with the interior of manifold IS, the connection being renderedfluid-tight by screwing up on clamping nut 2| and thereby compressinggland 24 tightly around lip B and against the lower end of boss 22.

Each of bellows holding, clamps I8, the details of which are shown inFigs. 5 and 6, comprises a pair of parallel plates 26 and 21 which aresecured to and spaced a predetermined-distance apart by a member 28. Ifdesired, a single elongated member 28 may serve to support a-pluralityof clamps I8, as indicated in Fig. 1. Both plates 26 and 21 extendlaterally beyond the sideedges of member 28, the portions of said plateson each side of said member constituting a holding or clamping devicefor the bellows end of one thermostatic assembly. As shown, the bottomplate 21 is solid and serves as a support for the movable end wall ll ofthe bellows while the top plate 26 is slotted at 29 so as to receive thethreaded boss H, the shoulder between said boss and bellows head I llabutting against the under surface of said plate. It is obvious thatwith this construction the expansion of each of the bellows is limitedto a predetermined amount with the result that the volume of thethermostatic assembly is correspondingly limited during the chargingoperation.

Returning now to the general arrangement of equipment illustrated inFig. 1, each of manifolds ii is connected at its inner end to a supplychamber 30 of any suitable construction to which are connected acharging liquid supply line II, and exhaust line 32 which serves both tocreate an initial vacuum in the manifolds i6 and the thermostaticassemblies and also to remove the charging liquid remaining in themanifolds after 1 the assemblies are completely filled, and a secondexhaust line 33 through which a high vacuum is created in the manifoldsand thermostatic assemblies. Lines 3| and 32 are controlled by valves 34and 35, respectively, of any suitable construcduring final exhaustion ofthe thermostatic as-' semblies, is effectually prevented by the use of abellows sealing member 38 one end of which is secured to the movablevalve member "while the other end is tightly clamped between valve body40 and bonnet 4|. I a

The charging liquid, which may be of any suitable character, is suppliedto lines II from a main supply tank 42 through suitable pipe lines Band44, each of the latter having interposed therein a stop valve 45 of anydesired construction and a check valve 46. Main supply'tankfl ispreferably positioned at a higher level than chambers 30 and manifoldsIt in order that the charging liquid may tend to flowfrom the tank tothe assemblies by gravity.

Means may also be provided for subjecting the charging liquid in supplylines I, chambers 30 75 I and manifolds to suflicient pressure to insureper open end tightly clamped between said casing and plate and asuitable spring 53 interposed -between the inner surface of plate 5| andthe movable end wall 54 of the bellows 52, said spring tending to expandthe bellows within casing 53, The interior oi'bellows member 52communicates with pipe 41 and also'with a suitable pressure gauge 55(Fig. 1). The space between the outer surface of bellows 52 and theinner surface of casing 53 constitutes a pressure chamber 55 which isconnected to asource oi! pressure such as an air compressor 51 of anysuitable type through a pipe line '58, communication between the aircompressor and said space being controlled by a cock 53 which in itsnormally closed position vents the pressure chamber 55 to theatmosphere.

Returning now to the exhaust lines 32 and 33 leading from each ofchambers 33, it will be seen that lines 32 are connected through a pipe53 with the top of a tank orcontainer 5| which serves both as apart ofthevacuum creating system and as a temporary or auxiliary reservoir forthe charging liquid which remains in and is withdrawn from the manifoldsl5 and chambers 33 after each charging operation. The top of tank 5|walso communicates with another pipe 52 which is in turn connected to anexhaust line '53 leading to the plant or low vacuum pump 54. The flowthrough exhaust line 53 is controlled by a suitable valve 55. Pipe 52and line 53 are also connected with a pipe -55.which may be placed incommunication with the atmosphere by the opening of a valve 51. i

. Suitable connections are also provided between mainsupply tank 42 andauxiliary reservoir 5| so that the charging liquid which is accumulatedin the latter'may be periodically returned to the former. As shown, aliquid return line 58 extends fronia point within and near the bottomof, tank 5| upwardly to a connection with one of lines 44 at apointintermediate valve 45 and the connection between lines 44 and 43.The flow through pipe 53 .is controlled by a suitable valve 53. Pipe 53is also'provided with a suitable, couwith exhaust line 53 atapointintermediate valve 55 and'vacuum pump 54. Communication betweenlines 1| and is controlled by a su table valve 12 interposed in a pipe13 which cross connects these two lines. Line 1| may also be Y connectedwith the atmosphere through a. section of pipe 14 under the control of asuitable valve" 15 so that during the charging operation the liquid intank 42 may be subjected to atmospheric pressure. If desired, tank 42may be provided with a suitable gauge 15 for indicating the level of theliquid therewithin.

Each high vacuum exhaust line 33 is. connected to a high vacuum pump 11through a pipe 13,;

the junction of lines 33 and pipe 13 being connected to a suitablevacuum tubing 33.,

In charging thermostaticassemblies by the method and apparatusdisclosed, the assemblies are first connected to the system by placingtips 3 of the thermostatic bulbs 8 in communication with passages 23 ofthe sealing connectors H, as indicated in Fig. 3, while the bellows endsof the assemblies are mounted in clamps IS in the manner illustrated inFigs. 5 and 6. It is assumed that at this time all of the valves of theentire system are closed with the exception of these connecting pressuregauges 55 to their associated pressure pots 43. Valves 35 and 65 inexhaust lines 32 and 53, respectively, are then opened so as to contactthe manifolds l5 and chambers 33- tothe plant or low vacuum pump 64through lines 32, pipe 53, tank 5|, pipe 52 and line 53, the air flowbeing indicated by the arrows in Fig. 1 bearing the single cross marks.After the socalled plant or low vacuum has been created in thethermostatic assemblies so as to remove therefrom the major portion ofthe air and moisture originally contained therein, valves 35 are closedand the packless high vacuum valves 35 are opened, thereby connectingmanifolds I5 and chambers 33 to high vacuum exhaust lines 33 andpermitting the assemblies to be further evacuated by high vacuum pump 11through lines 33 and pipe 13, as indicated by the double crossed arrows.

This second stage of evacuation is continued until a pressure .of 50microns or less is indicated on the vacuum gauge 13, at which timevalves 35 are closed. 7

The charging liquid valves 34 and 45 are then opened so asto permit thecharging liquid to flow frornmain. supply tank 42 downwardly throughlines 43, 44 and 3| into chambers 33,

manifolds l5 and the thermostatic assemblies 'under the influence ofatmospheric pressure which is admitted to the top,.of tank 42 by openingtoallow some ofthe charging liquid to flow into and fillthe'interiors-oi bellowsmembers 52 of pressure pots 43 and extend thelatter to their fuli length. it being understood that at this time cocks53 are closed so as to vent pressure chambers 55 to the atmosphere.After valves 34 have remained open a suilicient length of time to permitthe charging liquid to fill the bellows-members 52, chambers 33,manifolds l6 and as much of the thermostatic assemblies as can be filledunder atmospheric pressure and the forceof gravity; cocks 53 are openedso as to admit air under pressure from compressor 51 to the pressurechambers 55 of pressure pots 43, the air pressure moving the bellows'members 52 upwardly and thereby forcing some of the charging liquidcontained in said bellows out of pets 43 and placing all of the liquidin pipes 41, lines 3|, chambers 33, manifolds l5 and the thermostatii:elements under a pressure 'equal-to that admitted to chambers 55. Thispressure, which will be indicated on gauges 55, willexist in.,lines 44only as far as check valves 45. The flow oi air and liquid during thisfilling operation is indicated by the arrows bearing triple cross marks.

gauge 13 through valve 15. Valves 43 are also opened at this time a Itis to benoted that with' this arrangement.

. liquid of any of the pressure air because of direct contact therewith,one of the conditions which it is the object of the present invention toavoid.

After the pressure has remained on the charging liquid for a sufllcientperiod of'time to insure proper filling of all of the th rmostaticelements, the portions of tips 9 exten g below clamping nuts 2| ofsealing connectors H are pinched to-' gether with a suitablecrimpingtool not shown) so as to prevent further ingress or egress of liquid toor from the thermostatic assemblies. The air pressure cocks 58 are thenclosedso as to vent pressure chambers 56 to the atmosphere and therebyreduce the pressure on the liquid between check valves-.44 andconnectors l'l. As soon as the pressure is thus relieved, bellowsmembers 52 are expanded under the combined influence of the hydrostatichead of liquid and springs 53, 'the increased volume within said bellowsmembers being refilled with charging liquid drawn through check valves46. Charging liquid valves 34 are then closed and valves 35 in exhaustlines? 32 opened so as to apply the suction of plant vacuum pump 64 tolines 32, chambers 30 and .manifolds l6. Then, when the ends of tips 9of the thermostatic assemblies are removed from connectors H, thediiference'in pressure created by the suction applied throughlines 32and the atmospheric pressure exerted at the open ends of passages 20 ofconnectors Il will force whatever charging liquid remains in manifoldsI6, chambers 30 and the-portions of lines 3| below valves 34 throughlines 12 and pipe Bliinto tank 6|. The direction of flow of the liquidand air during this part of the procedure is indicated by the arrowsbearing the single cross marks. As soon as all of 'the liquidremaining'in the system below valves I4 has been drawn into tank Bl,valves 35 are closed and the system is ready to repeat the chargingcycle.

After the thermostatic assemblies have been removed from the chargingequipment, the portions of tips 9 extending beyond the pinched togetherpoints are cut off and the ends of the tips are welded to thepermanently closed condition indicated in Fig. 2.

In the arrangement of apparatus illustrated in Fig. 1, two sets ofmanifolds and associated equipment are shown. While both sets may beoper-' ated simultaneously so that all of the thermostatic assembliesconnected thereto will. be exhausted and charged at the same time, thisarrangement is additionally advantageous in that it permits practicallycontinuous operation by so manipulating the valves that the assembliesconnected to one set of manifolds are being evacu-, ated at the timethat those connected to the other set are being charged.

After a period of repeated charging operations, it will be desirable totransfer back to main supply tank 42 the charging liquid which hasaccumulated in tank ll, thereby permitting this liquid, which wouldotherwise be wasted, to be used again. In order to ei'fect this transferof liquid fromtank 4| to tank 42, exhausting and charging operationsmust be discontinued and valves 45 and I5 closed so as to preventfurther flow of liquid out to the upper portion of main supply tank 42-on top of the liquid in said ta through line I i, thereby creatingpartial vacuum By then opening valve 84 in line I, the differencebetween the atmospheric pressure exerted on the top of the liquidin'tank II and the partial vacuum existing. in the top of tank 42 causesthe liquid to flow from tank 6i upwardly through line 80, a portion ofline '44, and line 43 into tank 42. The directions of flow ofair andliquid during this operation are indicated by the arrows bearingquadruple cross marks. w

Whenever it becomes necessary to replenish, the supply of liquid in thesystem, coupling Ill in line 58 may be broken and the upper portion of,said line provided with an adapter whereby liquid may be drawn up fromany suitable container into tank 42 by creating a partial vacuum in saidtank in the manner Just described. After a suitable amount of liquidhasbeen thus supplied to.

tank 42, it maybe conditioned so as to free it of air by closing valve68 in line 68 but continuing the evacuation of the upper portion" oftank 42 through pipe I I.

' There are thus provided by the present invention both a novel methodand new and improved apparatus for charging thermostatic assemblies ofthe liquid expansion type which make possible performance of thecharging cycle in a relatively simple and efiicient manner and which arealso particularly well adapted to operationon a pro duction basis. Theprocedure of the method involved in the invention comprises a seriesofre- .lated steps which lend themselves to practically continuousproduction by the simple expedient of dividing the assemblies into twoor more groups and applying the cycle of the method to these groups indifferent phases. The apparatus provided is of simple character,embodies a minimum of moving parts, and, with the exception of theinitial and final connection and disconnection of the assemblies,requires only the opening and closing of various valves in apredetermined sequence in order to carry outthe entire cycle. By

useof the method and apparatus of the present invention'it is possibleto illl thermostatic assemblies with definite and predeterminedquantities of liquid and to insure that no air, moisture or otherforeign matter remains in the assemblies after the-charging operation iscompleted; it will also be noted .that the charging liquid is at-alltimes protected against contamination. Furthermore, the procedure andequipment are so arranged that there is no loss orwastage of thecharging liquid, the quantities thereof which remain in the systemaftereachchar'ging cycle being ultimately returned to the sourceofsupply and used over again. The apparatus of the invention also includesnovel means for supporting the thermostatic assemblies and connectingthem to the charging system, and for forcing'the liquid into theassemblies under pressure so as to insure proper filling thereof.

tures thereof, has been described with some particularity, it will beobvious that the invention is not limited to the apparatus shown. in thedrawings but is capable of a variety of mechanical embodiments. Forexample, while two sets of charging manifolds and associated equipmenthave been shown and described, is apparent that any suitable number ofsets may be utilized; if desired, only one set need be employed,although in this event the rate of production would not be as great.Likewise, it is apparent that many of the structural elements may beomitted, .or may be 5 used in other combinations for the attainment oftheir intended purposes. For instance, the invention may be employed inthe charging of thermostats which are only partially filled with liquid,in which case the pressure filling mechanism might be unnecessary.

. Various other changes, some of which will now readily suggestthemselves to those skilled in the art, may be made in the specificnature of the procedural steps and in the form, details of constructionand arrangement of the parts of the ap-. paratus without departing fromthe spirit of the invention. Reference istherefore to be'hadto theappended claims for a definition of the limits of the invention.

What is claimed is:

l. A method of charging a thermostatic assembly comprising the steps ofsubjecting said assembly to a relatively high vacuum to evacuate thesame, flowing a quantity of thermo-responsive liquid into said evacuatedassembly under atmospheric pressure, and then as a separate step aftersaid assembly has been filled at atmospheric pressure applying airpressure to produce an in-- creased pressure on said liquid whilepreventing contact of the air with said liquid to force an additionalquantity of liquid'into said assembly under a pressure greater thanatmospheric.

2. A method of charging a thermostatic assembly comprising the steps ofsubjecting said assembly to a plurality of successively higher values ofvacuum to evacuate the same, flowing a quantity of thermo-responsiveliquid into said greater than atmospheric.

evacuated assembly under atmospheric pressure, and then as a separatestep after said assembly has been'fllledat atmosphericpressure applyingair pressure to producev an increased pressure on said liquid whilepreventing contact of the air with said liquid to force an additionalquantity of liquid into said assembly under a pressure 3'. A'method ofcharging a thermostatic assembly comprising the steps of evacuating saidassembly, utilizing the vacuum thuscreated for causing a supply ofthermo-responsive liquid sub-- iected to atmospheric pressure to fiowinto said assembly, and then as a separate step after said assembly hasbeen filled at atmosphericpressure applying air pressure to said liquidto produce a pressure thereon greater than atmospheric while preventingcontact of the air with said'liquidto.

insure proper filling of the assembly, 7

- 4. A method of charging a thermostatic-as sembly of 'the liquidexpansion type comprising the steps of evacuating said assembly,utilizing the vacuum thus created for causing a supply oftheme-responsive expansible liquid subjected to e .atmospheric pressureto fiow into said assembly, a thenas a separate step after said assemblyhas been filled at atmosphericpressure applying air pressure to saidliquid to produce a pressure thereon greater than atmospheric whilepreventingcontact 01' the air with said liq to insure complete fillingof the assembly, and limiting the 5. A method of charging a thermostaticassembly of the liquid expansion type including an" expansible bellowscomprising the steps of evacuatingsaid assembly, utilizing the vacuumthus created for causing a supply of thermo-responsive expansible liquidsubjected to atmospheric pressure to flow into said assembly, and thenas a separate step after said assembly has been filled at atmosphericpressure applying air pressure to sembly of the liquid expansion typecomprising the steps of connecting the assembly to a charging manifold,applying a source of vacuum'to said manifold until said assembly isevacuated,

then connecting said manifold to-a supply of thermo-responsiveexpansible liquid ,subjected to atmospheric pressure and fiowing aquantity thereof into said manifold and assembly, and

- then as aseparate step after said assembly has been filled atatmospheric pressure applyingair pressure to the liquid in said manifoldto produce apressure thereon greater'than atmospheric while preventingcontact of the air with the said liquid .until an additional amount ofliquid has been forced into said assembly sufiicient to completely fillthe latter.

7. A method of charging a thermostatic assembly comprising the steps ofconnecting the assembly to a charging manifold, applying a source ofvacuum to said manifold until saidmaining in said manifold when saidassembly is disconnected therefrom out of the manifold and into areservoir by applying said source of vaeuum to said manifold throughsaid reservoir.

8. A method of charging a thermostatic assembly of the liquidexpansion'type comprising the steps of connecting the assembly toacharging manifold, successively applying sources of low and high vacuumto said manifold until said as sembly is evacuated, then connecting'saidmanifold to a supply of thermo-responsive expansible liquid subjected toatmospheric pressure. and flowing a quantity thereof into said manifoldand i assembly, then subjecting the liquid in said manifold to apressure greater than atmospheric until an; additional amount of liquidhas been forced into said-assembly sufilcient to completely fill thelatter; closing communication between said assembly and manifold, anddrawing the liquid remaining in said manifold when said assembly isdisconnected therefrom out of the manifold .andinto a reservoir byapplying said source of low vacuum to said manifold through saidreservoir. t I

9. A method of simultaneously char ing a plurality of thermostaticassembliesof. the' liquid expansion type each having an open end andincluding an expansible bellows member comprising the steps ,of bringingthe open ends of said assemblies into sealed communication with amanifold, sosupporting the expansible bellows members of said assembliesas to limit the expansion thereof to a uniform predetermined extent, ap

plying a source of vacuum to said manifold until all of said assembliesare evacuated, then connecting said manifold to a supply ofthermo-responsive expansible liquid and forcing said liquid into saidmanifold and assemblies under sufficient pressure to completely fill allof the latter, crimping the open ends of said assemblies to preventfurther communication with said manifold, and then disconnecting theassemblies from the manifold while subjecting the latter to a source ofvacuum to prevent loss of the liquid remaining therein.

10. In apparatus for charging a thermostatic assembly, the combinationof a filling pipe, means for placing the interior of said assembly in.sealed communication with said pipe, means for supplying a quantity ofcharging liquid to said pipe whence it flows into said assembly, areservoir,

' means for connecting said reservoir to said pipe,

and means forv creating a suihcient vacuum in said reservoir to drawinto the reservoir whatever liquid remains in said pipe when saidassembly is disconnected therefrom after the charging operation.

11. In apparatus for charging a thermostatic assembly of the'liquidexpansion type, the combination of a manifold, means for placing theinterior of said assembly in sealed communication with said manifold, asource of vacuum, a container for holding asupply of thermo-responsiveexpansible liquid, means for successively connecting said source andsaid supply to said manifold, means for placing the liquid thus suppliedto said manifold under sufficient pressure to completely fill theassembly therewith, and means for returning the liquid remaining in saidmanifold to the supply after the charging operation.

12. In apparatus for charging a thermostatic assembly of the liquidcontaining type, the combination of a manifold, means for placing theinterior of said assembly in sealed communication 7 with said manifold,a source of vacuum, a container for holding a supply ofthe'rmo-responsive liquid, -means for successively connecting saidsource of vacuum and said supply to said manifold, means for placing theliquid thus supplied to said manifold under sufficient pressure tocharge the assembly therewith, and means including said source of vacuumfor returning to said supply the liquid remaining in said manifold afterthe charging operation.

13. In apparatus for charging a thermostatic assembly of the liquidcontaining type, the combination of a manifold, means for placing theinterior of said assembly in sealed communication with said manifold, avacuum pump, a main supply'tank containing a quantity ofthermo-responsiveliquid, conduits connecting said pump and tank withsaid manifold, valves in said conduits for controlling the connection ofsaid pump and tank to said manifold, a source of pressure greater thanatmospheric, means for transmitting'the pressure of said source to theliquid in the conduit connecting said tank and manifold and I 'anyliquid which may be withdrawn from the latter by the suction of theformer. l

14. In apparatus for charging a thermostatic assembly, the combinationof a fllling pipe, means for placing the interior of said assembly insealed communication with said pipe, a main supply tank containing aquantity of charging liquid, a conduitconnecting said tank with saidpipe, a

source of pressure greater than atmospheric, means for transmitting thepressure of said source to the liquid inthe conduit connecting said tankand pipe and thereby forcing said liquid into said assembly, anauxiliary tank, means for withdrawing into said auxiliary tank whateveramount of charging liquid remains in said pipe when the assembly isdisconnected therefrom after the charging operation, and means forreturning the liquid in said auxiliary tank to said main tank.

15. In apparatus for charging a thermostatic assembly, the combinationof a filling pipe, means for placing the interior of said assembly insealed communication with said pipe, a main supply tank containing aquantity of charging liquid, a conduit connecting said tank with saidpipe, an auxiliary tank, means for withdrawing into said auxiliary tankwhatever amount of charging liquid remains in said pipewhen the assemblyis disconnected therefrom after the charging operation, a conduitconnecting said main and auxiliary tanks, a source of vacuum, and meansfor subjecting the contents of said auxiliary and main tanks toatmospheric pressure and said source of vacuum; respectively, whereinthe liquid in said auxiliary tank may be returned to said main tank.

16. In apparatus for charging a thermostatic assembly of the liquidcontaining type, the combination of a manifold, means for placing theinterior of said assembly in sealed communication with said manifold, avacuum pump, a main supply tank containing a quantity ofthermo-responsive liquid, conduits connecting said pump and tank withsaid manifold, valves in said conduits for controlling the connection ofsaid pump and tank to said manifold, a source of pressure greater iarytanks, a valve in said last named conduit,

and means for subjecting the contents of said auxiliary and main tanksto atmospheric pressure and the suction of said vacuum pump,respectively, whereby the liquid in said auxiliary tank may be returnedto-said main tank.

17. In apparatus for charging thermostatic assemblies of the liquidcontaining type from a manifold to which a charging liquid is supplied,a connector for placing the open end of once! said assemblies in sealedcommunication with said manifold comprising an externally threaded bodyportion having an unthreaded extension ofreduced diameter and a passagetherethrough communicating with the interior oi the manifold, a hollowclamping nuthaving threaded engagement with said body portion, acup-shaped guiding member mounted within said clamping nut and havingtelescoping engagement with said extension, and a sealing gland ofrelatively soft, compressible material mounted within said guidingmember and interposed between the bottom thereof and the end of saidextension, said clamping nut, guiding member and sealing gland havingaxially aligned openings therethrough to receive the open end of thethermostatic assembly.

PAUL E. cars. 1

